Age asymmetries in the aerial display of Little Gulls Larus minutus
Atlantic seabirds , Volume 2 - Issue 2 p. 57- 67
Aspects of age differences in the aerial display of Little Gulls Larus minutus are described based on fieldwork carried out in May 1983 in the Lauwersmeer area, The Netherlands. Aerial displays occur when an initiator or ‘sender’ approaches a ‘receiving’ individual. The sender initially makes (individually identifiable) kay notes, followed by several ke-kèh repeats. Once the sender has approached the receiver to within a few meters, it increases flight speed, jerks up the head to almost a vertical position whilst starting to call a repeated ke-kôo. The head-up part of the display is rounded off with a short glide over the receiver, but often the display is aborted somewhere along the sequence. This is especially the case when immatures are the initiators. Immatures seem particularly keen to exercise the display, and when doing so preferentially act towards adults. During display flights between adults, receivers tended to respond with their own display flights. However, in aerial interactions initiated by immatures the receivers tended to either flee or to retaliate by attack. I suggest that the aerial display presents a compound quality signal (possibly derived from aerial mosquito-catching movements), that requires much physical and social practising, even during the immature stages of life.
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